ERL water pump

Daniel Houlton houlster at user2.inficad.com
Sun Apr 4 06:13:59 GMT 1999


I got my ERL Aquamist pump earlier this week.  Turns out it's the newer
'Race' model that puts out a much higher pressure and volume than the 
standard pump.  I did some bench testing and figured I'd post the results
in case any one's interested.

I powered the pump from my truck battery with jumper cables.  I also did
the tests with the truck running.  It was substantially lower (~25%) 
without it running.

I ran all the tests for 1 minute into a measuring cup in ml.  I converted
them to gph by multiplying by .0158503  ( I got this number from one of
those super duper shareware convert damn-near-anything utilities for 
Win95).

The pump came with one ERL .7mm nozzle.  They have a wide range from .1mm
to 1mm in .1mm increments.

I also got some "mister nozzles" from McMaster Carr.  These are a full
cone style.  I'm not sure of the orafice size.  Just the flow rates they
published for them.  They are

M-1 --> .63 gph @ 40 psi
M-2 --> 1.26 gph @ 40 psi
M-3 --> 1.9 gph @ 40 psi

These were their 3 smallest ones.  They ran all the way up to around 9 gph
I think.  McMaster also has the "Instant Connect" hose connectors.  These
are the nice ones that you just push the hose in and it locks.  To unlock,
you hold the little ring back (in the opposite direction) and pull the
hose out.  These are the same type ERL uses.  Very nice and work like a
charm.

All the nozzles produce an extremely fine mist of water.  The M-1 was the
best I assume because of the much higher pressure.  They all looked more
like a fog almost than a fan of water.

Here's the chart of the results.  I also ran tests of 2 nozzles in parallel
using a tee connector.

---------------------------------------------------
|gal/hr |      |   M-1  |   M-2  |   M-3  |  .7mm 
|-------|------------------------------------------ 
|       |      |  1.59  |  2.46  |  3.17  |  3.57
|       |------------------------------------------ 
|  M-1  | 1.59 |  3.01     3.49     3.96   
|  M-2  | 2.46 |  3.49     4.20     4.68
|  M-3  | 3.17 |  3.96     4.68     4.99
|  .7mm | 3.57 |
---------------------------------------------------

I also measured static pressure on one end of the tee with each of the 
single nozzles on the other.  It only went up to 200 psi so I'm not sure
of the pressure for the M-1.

M-1  >>> 200 psi
M-2  170 psi
M-3  140 psi
.7mm 115 psi

Also, the pump has 3 wires.  Power, ground and what the documentation says
is a 0 - 12v signal wire.  Grounding the signal wire turns the pump off.  At
about 1.5v, the pump comes on.  Varying the voltage on the signal wire didn't
change the pump output any.  It was still on or off.  I'm thinking now the 
MF2 controller they sell for it must send a variable frequency to control
the pump output rather than a variable voltage as I had thought (hoped).

They supplied a pressure switch to turn the pump on when not using the 
MF2.  It is a Normally Closed type that goes in the signal wire which is
hooked to ground.  At 10 psi (adjustable), the switch opens, the signal is
no longer grounded and the pump comes on.

I've got it in an Excel sheet with more detail, part numbers, etc. if
anyone's interested.  It will be a couple days, but I can send it out to
whoever wants it.


--Dan
houlster at inficad.com
http://www.inficad.com/~houlster/amigo.htm



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